* {
  box-sizing: border-box;
}

:root {
  color-scheme: light dark;
  --bg: #f5f5f5;
  --text: #1d1d1f;
  --card: #fff;
  --border: #ddd;
  --hover-bg: #1d1d1f;
  --hover-text: #fff;
}

body {
  min-height: 100vh;
  margin: 0;
  font-family: Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
}

main {
  width: min(520px, calc(100% - 32px));
  margin: 0 auto;
  padding: 48px 0;
}

h1 {
  margin: 0 0 24px;
  font-size: 32px;
  line-height: 1.2;
}

nav {
  display: grid;
  gap: 12px;
}

a {
  display: block;
  padding: 18px 20px;
  color: var(--text);
  font-size: 20px;
  font-weight: 700;
  text-decoration: none;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
}

a:hover,
a:focus {
  color: var(--hover-text);
  background: var(--hover-bg);
  outline: none;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --text: #f2f2f2;
    --card: #1f1f1f;
    --border: #363636;
    --hover-bg: #f2f2f2;
    --hover-text: #121212;
  }
}

@media (max-width: 520px) {
  main {
    padding-top: 28px;
  }

  h1 {
    font-size: 28px;
  }

  a {
    font-size: 18px;
  }
}